Aircraft seat

ABSTRACT

An aircraft seat includes a seat cushion and a seat back. The seat cushion has a rear portion along the seat back and a front portion of complementary shape to the rear portion to form a complete seat cushion. The rear portion moves between a raised position and a lowered position. A coupling arrangement connects the front portion to the rear portion so that when the front portion is in the raised position along the seat back the front portion is in the lowered position, in which at least part of it is retracted under the rear portion. When the rear portion is in its lowest position along the seat back the front portion is in a raised, advanced position at the same height as the rear portion to form therewith the seat cushion of the seat for receiving a seated passenger.

This application is a continuation of application Ser. No. 10/454,889,filed Jun. 5, 2003 now U.S. Pat. No. 6,742,743.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a new type of aircraft seat.

2. Description of the Prior Art

Available space in an aircraft is an ongoing problem. To maximize theprofit on an aircraft flight, the greatest possible number of passengersmust be carried. A seat must be provided for each passenger. The problemthen arises of providing the greatest number of seats in a given space,that of the aircraft cabin. It is also necessary for the passengers tobe comfortable.

International safety standards impose a minimum space for eachpassenger. For example, in the event of an accident, if the head of apassenger is thrown forward, it must not strike the back of the seat infront, the passenger being secured by a seat belt, of course. If thisstandard is only just complied with, the seat cushion occupies twothirds of the distance between two successive seat backs and theremaining third is available for the legs of the seated passenger andfor moving around, in particular to access the seat.

In economy class in particular, the small space for moving aroundbetween two rows of seats generally prevents natural movement, requiringa passenger to move sideways and to lean over, to adapt to theinclination of the seat backs.

An object of the present invention is to provide a new aircraft seatfacilitating movement of passengers between two adjacent rows of seats.

SUMMARY OF THE INVENTION

To this end, the present invention proposes an aircraft seat including aseat cushion and a seat back, wherein the seat cushion has a rearportion along the seat back and a front portion, of complementary shapeto the rear portion, to form a complete seat cushion. The rear portionof the seat cushion is mobile between a raised position and a loweredposition. Also includes a coupling linkage connecting the front portionof the seat cushion to the rear portion so that when the front portionis in the raised position relative to the seat back at least a part ofthe front portion is in a lowered position, of the seat cushion underthe rear portion, and when the rear portion is in its lowest positionrelative to the seat back at least a front segment of the front portionis in a raised, advanced position at the same height as the rear portionto form therewith the seat cushion of the seat for receiving a seatedpassenger.

A seat according to the invention provides more room to move around whenthe front portion of the seat cushion is retracted under the rearportion, while offering a comfortable seat with good support for thethighs when the front portion is aligned with the rear portion in afully extended position for seating a passenger.

In one embodiment of a seat according to the invention the rear portionof the seat cushion is adapted to slide along the fixed frame or beam towhich the seat back is mounted.

The front portion moves from its lowered (retracted) position to itsraised (advanced) position with a movement that is a combination of amovement in translation toward the front and a rotation, for example. Itis nevertheless also possible to make provision for only a movement intranslation or only a rotation.

In one embodiment, the front portion of the seat is connected to therear portion by at least two links forming a deformable trapezium andone of these links is connected by a third link to a fixed point.

The front and rear portions of the seat cushion preferably each accountfor substantially half the surface area of the seat cushion when theyare at the same height.

In an advantageous embodiment, the seat includes latching means forlatching the rear portion of the seat cushion in its raised position.The seat can then be used for a child, in the manner of a highchair.

For improved resistance to heavy loads, the seat includes a fixedreinforcement disposed substantially vertically underneath it, forexample, and the rear portion of the seat cushion has a housing toreceive an upper portion of the reinforcement when the rear portion isin its lowered position. The reinforcement can consist of two verticaltubes linked by a transverse bar.

Details and advantages of the present invention will emerge more clearlyfrom the following description given with reference to the accompanyingdiagrammatic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a seat according to the invention in a “rest”configuration.

FIG. 2 is a side view of the FIG. 1 seat in an “in use” configuration.

FIGS. 3A to 3C are diagrams showing the movement from the configurationshown in FIG. 1 to the configuration shown in FIG. 2.

FIG. 4 is a partial front view of the seat shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The aircraft seat shown in the figures includes a seat cushion in twoparts, a seat back 2 with a headrest 4 at the top, and legs 6.

The seat has two legs 6 supporting the seat back 2 and the seat cushion.The legs are aligned with the seat back 2. For example, the seat caninclude two facing and substantially vertical beams fixed to the floorat the bottom. The bottom portion of the beams, close to the floor, thenserves as a base for the seat, and the upper portion is used to fix theseat back 2.

The seat shown in the drawings is fixed to the horizontal floor 8 of anaircraft cabin. An arrow 10 indicates the direction of movement of theaircraft in flight and defines a longitudinal axis. Thus in the figuresthe forward direction is to the left and the rearward direction is tothe right.

The seat cushion has a front portion 12 and a rear portion 14. The twoportions 12 and 14 have complementary shapes to form a complete seatcushion as shown in FIG. 2. The junction surface between the front andrear portions 12 and 14 of the seat cushion is substantially plane. Thisjunction plane 16 is inclined at approximately 45°. It extends upward inthe direction from the rear upwards to the front and forms a seatcushion junction line 18 transverse of the seat and substantiallyparallel to the seat back 2. The distance between the junction line 18and the seat back 2 is substantially equal to the distance between thejunction line 18 and the front edge 20 of the seat cushion, which is themost forward portion of the seat cushion when the front portion of theseat cushion is fully extended forward.

As can be seen in the figures, the front and rear portions 12 and 14 aremobile relative to each other and also relative to the fixed seat back2.

The rear portion 14 of the seat cushion can move in substantiallyvertical translation along the bottom portion of the seat back 2. Oneach side of the seat, at the level of the top portion of the legs 6,there is a pneumatic cylinder 22. Each pneumatic cylinder 22 is fixed atthe bottom end to the corresponding leg 6 and at the top end to anattachment lug 24 fastened to the rear portion 14 of the seat cushion.The rear portion 14 can be guided on the seat back 2 by co-operation ofmatching shapes of the rear portion 14 and the seat back 2, for example.Alternatively, guide fingers can be provided on the rear portion 14,each sliding in a corresponding groove in the beams forming the legs 6and supporting the seat back 2, for example.

The front portion 12 of the seat cushion is connected to the rearportion 14 by links. It is possible to provide a single set of linkssituated substantially in the median longitudinal plane of the seat ortwo sets of links symmetrically placed relative to that medianlongitudinal plane. In the latter case, the links are then on the sidesof the seat, for example, but in this case they are preferablystreamlined to prevent pinching fingers or objects. Other solutions canalso be foreseen. However, configurations in which the seat issubstantially symmetrical relative to its median longitudinal plane arepreferred. The remainder of the description applies to only one set oflinks.

Thus the front portion 12 is connected to the rear portion 14 by a toplink 26 and a bottom link 28. The links 26 and 28 are both disposed in alongitudinal vertical plane and define a trapezium. A first end of eachlink is attached to and pivots on the rear portion 14 of the seatcushion and the other end of each link is attached to and pivots on thefront portion 12 of the seat cushion. The respective attachment pointsof the top link 26 to the rear portion 14 and the front portion 12 arehigher than the points of attachment of the bottom link 28 to the rearportion 14 and the front portion 12, respectively.

Accordingly, the relative movement between the rear portion 14 and thefront portion 12 is a combination of rotation and translation movement.As can be seen in FIGS. 1 and 2, in the “in use” configuration (FIG. 2)the front portion 12 is almost horizontal and in front of the rearportion 14 and in the “rest” configuration (FIG. 1) the front portion 12is retracted relative to the rear portion 14 and at least part of it isunder the latter.

The lengths of the links and the positions of the attachment points arechosen so that in a first position the front portion 12 cooperates withthe rear portion 14 to form a seat cushion and in the rest position atleast part of the front portion 12 is retracted under the rear portion14.

Note that, as shown in the FIGURES, the bottom link 28 is connected by athird link 30 to a base 32. This connection to the floor couples themovement of the rear portion 14 relative to the seat back 2 with therelative movement of the front and rear portions 12 and 14 of the seatcushion.

The base 32 also carries a reinforcement formed by two vertical tubes 34linked by a transverse bar 36. FIG. 4 is a front view of thereinforcement. Note that, as shown in FIG. 4 and FIG. 1, the rearportion 14 of the seat cushion has two housings 38 facing the free topends of the tubes 34. The housings 38 are formed in the structure of therear portion 14 of the seat cushion. The tubes 34 are relatively farback, so that they do not impede the movement of the front portion 12 ofthe seat cushion. Their height is such that when the rear portion 14 isin its lowest position (see FIGS. 2 and 3C), the free ends of the tubes34 are in the housings 38.

How the seat works is described hereinafter with reference to FIGS. 3Ato 3C.

In FIG. 3A, the seat is in the rest or retracted configuration and apassenger is about to sit on it. The rear portion 14 of the seat cushionis in its highest position. This position can be defined in variousways, for example stop(s) on the seat back and/or the seat cushion, endof travel stops on the pneumatic cylinders 22, etc. The front portion 12of the seat cushion is retracted under the rear portion 14. Thisposition is defined by the lengths of the links 26, 28 and 30 and by theposition of the attachment points of the links. The pneumatic cylinders22 apply a spring return force to the rear portion 14 of the seatcushion in this highest position of the rear portion 14. Here the frontportion 12 of the seat cushion can come into contact with the tubes 34of the reinforcement placed under the seat. If necessary, thereinforcement can limit the movement of the front and rear portions 12and 14 of the seat cushion and thereby form the stop(s) defining thehighest position of the rear portion 14 and the retracted position ofthe front portion 12.

When the passenger begins to sit down (see FIG. 3B), he first comes intocontact with the rear portion 14. The passenger's weight applies a forcein opposition to the force exerted by the pneumatic cylinders 22, andthe rear portion 14 of the seat cushion therefore descends. Because ofthe third link 30, the bottom link 28 is pushed upward, entraining thefront portion 12 of the seat cushion. The front portion 12 then movesforward and pivots until it is virtually horizontal. The pneumaticcylinders 22 damp the downward movement of the passenger.

When the passenger is entirely seated (see FIG. 3C), his weight issupported primarily by the rear portion 14 of the seat cushion, which isin its lowest position, which can be defined in various ways, forexample by stop(s) limiting the downward movement in translation of therear portion 14 of the seat cushion. These stop(s) can be integratedinto the pneumatic cylinders 22 and/or the seat back 2 and/or the legs 6and/or the rear portion 14. Alternatively, the same effect can beobtained when the front portion 12 is positioned relative to the rearportion 14 to form a complete seat cushion, or by the reinforcementunder the seat, when the tubes 34 come into contact with the bottom ofthe corresponding housings 38.

In this position (see FIG. 3C), the reinforcement of the tubes under theseat assists it to absorb high forces. The transverse bar 36, by linkingthe two tubes 34, also increases the resistance of the seat to sideloads. Thus the seat can absorb longitudinal accelerations of 16 g andtransverse accelerations of 7 g (1 g =9.81 ms⁻²).

In a different embodiment, latching means can be provided to latch theseat in its rest position (see FIGS. 1 and 3A), in which the rearportion 14 of the seat cushion is in the raised position and the frontportion 12 is retracted under the rear portion 14. There can be multiplelatches. For example, latches can be integrated into the pneumaticcylinders 22 to prevent the rear portion 14 from descending. There canalso be a latch to prevent the rear portion 14 of the seat cushion fromdescending. The link 30 can also be latched. In this latter case, thelatching means are advantageously provided with foot-operated controlmeans.

Latching the seat in its rest position enables the seat to be used for achild. The child is then seated only on the rear portion 14 and istherefore raised up. Moreover, in this position the length of the seatcushion being limited to the rear portion is better suited to the sizeof a child. Thus young passengers can travel much more comfortably thanon conventional prior art seats.

The seat according to the invention is as comfortable for a passenger asa conventional aircraft seat. When seated, the distance between thefront edge 20 of the seat cushion and the seat back 2 can be identicalto that of a conventional seat. The passenger therefore has the benefitof equivalent thigh support. When he is not seated, the passenger hasmore room to move around, for example to take off a garment, or to placea bag in a luggage locker, etc.

If the space between two successive seats is too small, deep veinthrombosis problems can arise on long-haul flights. A seated passengerlacks room to move around and his blood does not circulate properly inthe legs. A thrombosis can then result. A seat according to theinvention can help to solve these problems. The passenger has more roomwhen he stands up. He can then move around, for example squat, withoutdisturbing his neighbors. This exercise encourages blood circulation andprevents thrombosis.

The movement of the seat cushion does not disturb the passenger when hesits down or stands up. He has no need to perform any particular gesturefor the seat cushion to be positioned correctly, unlike conventionalfolding seats, in which the whole seat cushion pivots from itssubstantially horizontal position of use to a substantially verticalrest position along the seat back. With conventional seats, movement ofthe seat cushion toward its horizontal position must be started with thehand before the passenger can sit down.

The seat according to the invention has the advantage of assisting thepassenger to sit down. The passenger comes into contact with the seatsooner and the last phase of his descent is damped, especially if theseat incorporates spring means.

Like aircraft seats in general, a seat according to the invention canaccommodate a life vest. The mechanism of the seat is compact and leavesa large free space under the seat, both in the rest configuration and inthe in use configuration. This free space can also be used for thecomfort of passengers and can provide space for the feet of thepassenger seated on the seat or the feet of a passenger seated behindthe seat.

Because of the increased room to move around between rows of seats, whenthe seats are not occupied embarkation and disembarkation times can bereduced. Passengers can move around more easily and therefore faster.

Other advantages are that, the flight crew and passengers can be servedmore easily, especially when the aircraft has at least two aisles. Ifone of the aisles is temporarily blocked and there is at least one rowof empty seats between the aisles, it is easy to move from one aisle tothe other, even with a trolley (or cart).

The present invention can be applied to seats of any shape. Themechanism described above can be adapted to suit virtually all seats.For simplicity, no armrests are shown in the drawings. Armrests cannevertheless be provided, either fastened to the seat cushion,preferably to the rear portion thereof, or to the seat back (or thelegs).

The present invention is not limited to the preferred embodimentdescribed above by way of non-limiting example. To the contrary, itencompasses all embodiments within the scope of the following claims.

For example, other kinematic systems could be envisaged between the rearportion and the front portion of the seat cushion. The top and bottomlinks could form a parallelogram, for example. In this case, therelative movement between the two portions of the seat cushion would bea movement in translation only. Alternatively, a single link could beprovided between the two portions of the seat cushion. Other mechanismswith a return point, like a swing, could be envisaged.

The movement of the front portion of the seat cushion being linked tothe movement of the rear portion, the spring return forces can equallywell be exerted on the front portion of the seat cushion or on amechanism connecting the two portions of the seat cushion to spring-loadthe rear portion toward its raised position. The spring return means areoptional. Obviously means for returning the seat cushion to the restposition are advantageous. Instead of providing spring means (pneumaticcylinders, springs, etc.), other means can also be envisaged (offsetcentre of gravity, counterweight, etc.).

1. An aircraft seat for an aircraft cabin, said aircraft seatcomprising: a frame member; a seat back mounted to said frame member; aseat cushion having a rear portion movably mounted to one of said seatback and said frame member and a front portion mounted adjacent saidrear portion, said front portion having a front end segment and a rearend segment opposite said front end segment; means for biasing said rearportion of said seat cushion between a raised position and a loweredposition, said means for biasing mounted between said rear portion ofsaid seat cushion and said frame member; means for moving said frontportion of said seat cushion from a first lower retracted position to asecond raised extended position whereby in said first lower retractedposition said rear end segment of said front portion of said seatcushion is moved substantially underneath said rear portion of said seatcushion and in said second extended position, said front portion ismoved to fully extend such that said front end segment of said frontportion of said seat cushion is moved to extend from said rear portionat substantially the same height as said rear portion of said seatcushion to provide a seat for a passenger.
 2. The aircraft seat asclaimed in claim 1 wherein said means for biasing is a spring.
 3. Theaircraft seat as claimed in claim 1 wherein said means for biasing is apneumatic cylinder.
 4. The aircraft seat as claimed in claim 1 whereinsaid means for moving said front portion of said seat cushion furthercomprises a four-bar linkage connecting said rear portion of said seatcushion with said front portion of said cushion; and a fixed link memberhaving one end fixed to a floor for said aircraft cabin and an oppositeend attached to at least one link of said four-bar linkage.
 5. Theaircraft seat as claimed in claim 1 wherein the movement of said frontportion of said cushion from said first lower retracted position to saidsecond raised extended position is a combination of a movement intranslation in a forward direction and a rotation.
 6. The aircraft seatas claimed in claim 1 further comprising means for supporting said rearportion of said seat cushion when said rear portion is in said loweredposition.
 7. The aircraft seat as claimed in claim 1 wherein said meansfor biasing said rear portion of said seat cushion biases said rearportion of said seat cushion towards said raised position.
 8. Theaircraft seat as claimed in claim 7 further comprising means forlatching said rear portion of said seat cushion at said raised position.